Device for heating metal-casting molds.



- A. c. ATKINSON DEVICE'FOR HEATING METAL CASTING M OLDS.

APPLICATION FILED 0m. 3. 1911.

1,280,631. I Patented Oct. s, 1918.

ED STATES. PATENT OFFICE.

ALFRED CHARLES ATKINSON, 0 WELLINGTON, NEW EALAND.

DEVICE FOR HEATING METAL-CASTING Moths] Specification of Letters Patent.

Patented Oct. 8, 191 8.

Application fi led October 3, 191?. Serial No. 194,580.

7 have invented new anduseful Improvements in Devices for HeatingMetal-Casting Molds; and I do hereby declarethe following to be a full,clear, and exact description of the same.

This invention has been designed in order,

to provide improvements in the heating of the molds used for castingsmall metal articles, and particularly used for casting artificialdentures and other dental work.-

These molds are formed by positioning a fusible wax model or pattern ofthe article to be cast in a metal flask'and surrounding it with aninvestment of plaster of Paris composition. This. mold is then heated tomelt the model so that the material of which it is composed, willdisappear and leave a mold of corresponding shape into which the. metalis run to form the casting themold being heated to insure of the properrunning of the molten metal under the pressure usually employed in thisclass of casting.

In the operation of this process, it is advisable that the mold shouldfirst be slowly heated to melt the fusible model or pattern and to expelthe moisture from the investment material, as its subjection to a quickheat renders it liable to uneven drying and consequently thedestruction. or distorting of the mold. After the moisture has beenexpelled the heat may be raised to heat the mold to the necessary degreeto provide for the efiective running of the metal. c

Theinvention consists in means whereby these voperationsof the initialslow heating and the subsequent quick heatingto a high degree, may beeffectively carried out, and;

also embodies means whereby a visible indication maybe giventhe operatorwhen the mold has been first sutficiently heated to exs. pel themoisture and then heated to thezpre-n determined degree necessary; for;the'casting; This feature of the invention is adaptedto be used inconjunction with ,the indicating means describcdin the specificationofmy application for Patent No. 123,143, dated:

30th September, 1916', and: which consists in a rod of material fusibleat a highejr temperri ature than'that to which: the mold isto be:heated, that is embeddedrat one of its ends' in aplug of a materialfusible at the tempera leading to the outside of such material. When theplug melts the rod is released and any approved shape incross sectionbut genture to which the mold is to be raised for casting purposes. Theplug is positioned within the investment material of the mold and .itsrod extends centrallyina tunnel falls to one side. of the tunnel therebyindi-,

cating the fact that the desired temperature has been reached.

In fully describing the invention reference will be made totheaccompanying sheet of drawings, in which:. ,g Figure l'i'saasectionalelevation of amolding flask ready for heating in the furnace.

Fig. 2' is a furnace.

Fig. 3 isan end elevation of the inma e;

Fig. 4. a side elevationthereof.

. Fig. 5 is a sectional end elevation ,,and-

Fig. 6 a sectional side elevation thereof, the molding flaskibeing shownin position in each figure. U Q' Referring first to Fig. 1, Arepresentsthe molding flask that is made of. metal and ,of,

erally of circular or elliptical shape. B represents the wax model orpattern that is embedded within the plaster of Paris .investment C inwhich also the runner holeB' leading to the model from one end of themum temperature toWhioh the mold is-tozbe' heated, one end ofwhich isheld in the plug D sorthat the rod will extend centrally with T in thetunnel E, and will then by gravity,-

fall to one side of the tunnel whenvthe plug D melts and loosensits-holdon the rod.

In thisinventionmeans'areeOIIibined-Rwith 7 p the rod D bywhich anindication-may bealso given when 'thetemperatureof the flask hasbeen-heated to the degree necessary to expel the moisture from the"investment. I

These means consist inasecond plug F of a l fusible metal orotherfusible material that is of such a nature as tofuse at a minimumtemperature slightly above that'joffthe boil Bing point ofi lwater, forinstance,'ati230 Fah., and which plug is arrangedonthe' rod f Dati'a-isuitalole distance from its end. Orm

instead of a plug,a'disk of 'the material plan of the lower part' offlask is also formed- D iS7 he plug of fusible j may beused. This plugor disk then occu pies a position within the tunnel E in the moldingfiaskand comes under the action of the heat of'the' flask so that whensuch heat reaches the specified degree,-,the plug:

ordisk will melt and thus show the operator that the mold has reachedthe required.

temperature and that all moisture is expelled therefrom. plug or disk Fshould. be at such a point on the rod i D" as tooccupy a position wellwitlrinthe mouth of the tunnel and thereby be: free from any directaction from the fiames of the furnace in which "the flask is "placediThe-melting ofthe plug, or disk-E will not inany way afiect' therigidity fthe rod and its subsequent function;

Referring now to the 'rem'ainingfigures of the drawings which showtheformoffurinace- *designedfor heating the mold, this is designed i tocause the heat from the burners to be evenly distributedaroundjthe wholecircumference of the. flask 'A'. and-thereby to I uniformly contents.

'. dic'atingi means; before i described may be;

, The furnace designed comprises astand G having a fiat rectangular opentopi or platform G at the opposite, ends-cf which, sockets' are formed."'Each Qf these sockets--'-is adapted to receivethe vertical stenr J of aflask support J which support is formed as an arc in which the'flask Awill 'rest; as'sh'own in Figs. 5* and 6. The flaskis thussupported atits two ends by means of the respective supports and it then extendsacrosstlie top of-the platform G"; The supports are made removable fromthe sockets H so that different sizes and forms of supports tocorrespond with the "different sizes' andshapes of flasks to beheated,maybe substituted-asrequired. The top of the furnace is formed asa cover'K of the. approximate semi-cylindrical formshown; that 1sadapted to rest 'upon the *edges' oftheplatfornr Gi This cover' is"lined. with asbestos lining K or withother approvedvlinsulatinggmaterial; It"there 'fore encircles 'thei'fiask A laid upon the'supportsJ and servesatoronserve the'heat around fsuchflask. The'endsof the flaskareposi- 1 tioned' adjacent to the'ends of'thecover andv these lattereitdsare made with sight i-apermesa Lthereimin a line approximately withthe?v center line. of such flask so that :therinviewedslwithout. raisingthe coverUrThe cover isralso'; formed with'za' vent or vents in in itsxtop for. the: escape of the" fumes and-to insure ofathepropernpdraftaround= tllGiSuTfabBZOf thefiaskzr The lowerqportion of the stand Orrframe:

is madeawith'ledges M arranged at inter-a vals in thevh'eight of the.stand and which are'f'adapted to receive and support: a plate N Zthat 1carries. the burner by which the-furs It is necessary that the-- heatthe whole area "ofthe' flasks Y of-thezburner main :may be provided witha will.

nace isheated. The distance ofc'tli'e burner beneath the flask istherefore adjustable at or arranged'inparallel verticallines'andspacedapart so Y that the flames will im pinge upon the flask upon theopposite sidesof. it's- "centei" line andthen follow the samewholecircumferential area of the flask, and any undue concentration of thehea't" upon the one portion the'reof will thereby be avoidedfi i coursearound theflask? In this manner the heat will beevenly distributed overthe The-frame may, if desired bejprovidfed with aga'ge bar P extendinghorizontally; across'it at'each GDCl OI SI'dQ and so disposedintrelatlon to the-burner that the height of' the'flamesth'ereof :inrelation to a sightline extendingbetween the-two bars, may be gaged bythe operator. The operator, -know' ing from previous experiment or use,the height of flame in relation to thissight line, that gives bestresults in the preliminary heating of the mold zbefore referred to, may

adjustrhis flame accordingly or insteadof these bars being; attached: tothe frame," a

bar It having; a similar"purpose may. be

fixed to the. sidcvor -end of the :burner: sup:-

porting plate-.N byimeans of a; .vertical.stay Ra .(FigsxQ and l) 1attachedc'to suchplate;

This bari may: be madenadjustable in its on the lower end of othefstay.o

cheightby adjustingfnutsw'or other means The usual air supply.aperture-orslot S"* regulating sleeve. S" (Fig.4) by meansof whichzjtheair supply: may. beadjusted; at@

"1. fln' a device: for heating metal casting molds, a mold support ng:frame" consisting:

in; a stand havinga horizontal open top withremovable mold restsxat each'end thereof; an ansu l ated zcover cfittingfover" suchjtop and I Yadapted to V inclose Y ther-mold," and a heatingburner supported: withinlthe loweriportion of fthe'z stand and adj ustablein: ,heig-ht' thereon,substantially asfspecified '2'. Tn device :for heating metal castingmolds;vv a the combination Jwith a i mold sup-' Y 7 porting framehavingan open horizontal topl' ,"with removable mold rests at ea'ch endthereoffoff-t a'sburner for 1 heating the *mold t Y arranged beneath'such open top: and formed 1 Y by a 'maini having: jetnozzles arranged:in. two: parallel irows :extending upward 3 from weasel such main inrespectively oppositely divergingi or vertical lines, substantially asspeci- 3. In a device for heating metal casting molds, a mold supportingframe mounted on a stand and formed by an open horizontal top withsockets arranged one at each end thereof, and mold rests adapted tosupport the mold each formedvby a curved cross bar and a vertical stemthat enters one of the sockets in the frame, substantially as specified.

l. In a device for heating metal casting molds, a mold supporting framemounted on a stand and formed by an open horizontal top provided withmeans for supporting the mold thereon and a burner ar ranged beneathsuch top and supported by the stand, in combination with an insulatedcover fitting over the stand top and formed with vision apertures in itsends, substantially as specified.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

ALFRED CHARLES ATKINSON. V

Witnesses:

W. ALEXANDER, v M. E; BROWN.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

. Washington, D. G.

